Wireless communication system and method therein for transferring at least part of services originally provided by a second station to a third station and a first base station in the system

ABSTRACT

The present disclosure provides a wireless communication system and method therein. The wireless communication system comprises: a first base station, second base station, third base station and user equipment, wherein the first base station and the second base station perform wireless data connections with the user equipment by adopting different carriers, and a trigger node triggers a transfer procedure in the case of judging a preset transfer condition of transferring a service to the third base station is satisfied, wherein the service is provided by the second base station to the user equipment, so that the user equipment releases the wireless data connection with the second base station and establishes the wireless data connection with the third base station, and thus the first base station and the third base station perform wireless data connections with the user equipment by adopting different carriers, wherein at least part of the service provided by the second base station initially is transferred to the third base station. According to an embodiment of the present disclosure, it can be ensured that the user equipment obtains optimized quality of service, while the efficiency of data transmission is improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/764,027, filed Jul. 28, 2015, which is a 371 of InternationalApplication No. PCT/CN2014/091867, filed Nov. 21, 2014, which claimspriority to Chinese Patent Application No. 201310597066.9, filed Nov.22, 2013. The entire contents of U.S. patent application Ser. No.14/764,027 are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present disclosure relates to the field of wireless communication,and particularly, to a wireless communication system and a method usedin the wireless communication system.

BACKGROUND OF THE INVENTION

Currently, in a wireless communication system, technology of carryingout wireless data connections with a plurality of base stations overdifferent carriers simultaneously by user equipment has been widelydiscussed. However, a solution under specific scenes has not beenlaunched.

SUMMARY OF THE INVENTION

A brief summary of the disclosure will be given below to provide basicunderstanding of some aspects of the disclosure. However, it shall beappreciated that this summary is neither exhaustively descriptive of thedisclosure nor intended to define essential or important components orthe scope of the disclosure but is merely for the purpose of presentingsome concepts of the disclosure in a simplified form and hereby acts asa preamble of more detailed descriptions which will be presented later.

Therefore, in view of the above circumstances, an object of the presentdisclosure is to provide a wireless communication system and a methodused in the wireless communication system, which are capable ofrealizing that in a wireless communication system in which a pluralityof base stations perform wireless data connections with user equipmentover different carriers simultaneously, if certain conditions aresatisfied, the user equipment is triggered to transfer part or all ofradio bearers between the user equipment and some base stations to otherbase stations. Thus, it is possible to ensure the user equipment obtainsideal service quality from the base stations, and effectively improveuplink and downlink data transmission efficiency.

According to an aspect of the invention, there is provided a wirelesscommunication system including a first base station, a second basestation, a third base station and user equipment, in which the firstbase station and the second base station perform wireless dataconnection with the user equipment over different carriers, and atriggering node triggers a transfer procedure if it judges apredetermined transfer condition for transferring services provided tothe user equipment by the second base station to the third base stationis satisfied, so that the user equipment releases wireless dataconnection with the second base station and establishes wireless dataconnection with the third base station, and thus the first base stationand the third base station perform wireless data connection with theuser equipment over different carriers, wherein at least part of theservices originally provided by the second base station is transferredto the third base station.

According to a preferred embodiment of the invention, the transferprocedure may further cause part of the services originally provided bythe second base station to be transferred to the first base station.

According to another preferred embodiment of the invention, thetriggering node may be the first base station or the second basestation.

According to another preferred embodiment of the invention, thetriggering node sends a transfer request to the third base station if itjudges the predetermined transfer condition is satisfied according to areceived mobility measurement result regarding a serving carrier of thesecond base station, the third base station performs a first admissioncontrol according to the transfer request and sends a transfer responseto the first base station and/or the second base station to notify aresult of the first admission control, in which the transfer responsecomprises at least one of the following: for which part of radio bearerof the user equipment that the third base station can performcommunication, a dedicated preamble code as required when makingsynchronized access to the third base station, system information of acarrier for communication between the user equipment and the third basestation, and configuration information of a control plane protocol forestablishing communication between the user equipment and the third basestation.

According to another preferred embodiment of the invention, if theresult of the first admission control indicates that the third basestation can not accept all radio bearers between the user equipment andthe second base station, then according to the transfer response sent bythe third base station or the transfer response sent by the third basestation and forwarded to the first base station via the second basestation, the first base station performs a second admission controlaccording to the result of the first admission control and notifies thesecond base station of a result of the second admission control.

According to another preferred embodiment of the invention, the firstbase station or the second base station sends, after acquiring a finalresult of the first admission control or the second admission control, anotification message to the user equipment to notify the user equipmentto perform the transfer procedure according to the final result and thetransfer response of the third base station, the notification messagecomprising at least one of the following: for which part of radio bearerof the user equipment that the first base station can performcommunication, for which part of the radio bearer of the user equipmentthat the third base station can perform communication, a dedicatedpreamble code as required when making synchronized access to the thirdbase station, system information of a carrier for communication betweenthe user equipment and the third base station, and configurationinformation of a control plane protocol for establishing communicationbetween the user equipment and the third base station, and the userequipment releases, after receiving the notification message, radiobearers unacceptable by the first base station and the third basestation, and releases the wireless data connection with the second basestation and performs synchronized access to the third base station atthe same time.

According to another embodiment of the invention, if data of the first,second and third base stations is directly routed from a core networkbefore triggering the transfer procedure and after completing triggeringof the transfer procedure, the second base station performs dataforwarding operation to forward data of a first radio bearer acceptableby the third base station to the third base station according to theresult of the first admission control, and further performs dataforwarding operation to forward data of a second radio bearer acceptableby the first base station to the first base station according to theresult of the second admission control, and the first base station orthe second base station notifies the core network to switch a pathcorresponding to the second radio bearer to the first base station.

Preferably, if synchronized access to the third base station by the userequipment succeeds, the third base station notifies the core network toswitch a path corresponding to the first radio bearer to the third basestation; otherwise, if the synchronized access to the third base stationby the user equipment fails, the user equipment notifies the first basestation, and the first base station notifies the second base station andthe third base station after performing a third admission control, sothat data of a third radio bearer acceptable by the first base stationin the first radio bearer is forwarded to the first base station, andthe first base station notifies the core network to switch a pathcorresponding to the third radio bearer to the first base station and torelease a core network bearer corresponding to a radio bearerunacceptable by the first base station in the first radio bearer, andnotifies the user equipment to release the radio bearer unacceptable bythe first base station in the first radio bearer at the same time.

According to another preferred embodiment of the invention, if data ofthe second base station is forwarded from the first base station, thefirst base station stops forwarding data to the second base stationafter completing confirmation of the first admission control or aftercompleting the second admission control, and the second base stationperforms data forwarding operation to forward data of the first radiobearer acceptable by the third base station to the third base stationaccording to the result of the first admission control, and furtherperforms data forwarding operation to forward data of the second radiobearer acceptable by the first base station to the first base stationaccording to the result of the second admission control.

Preferably, the first base station performs data forwarding operation toforward the data of the first radio bearer to the third base stationafter completing confirmation of the first admission control, or thefirst base station performs data forwarding operation to forward thedata of the first radio bearer to the third base station after receivinga message that synchronized access to the third base station by the userequipment succeeds.

Further, preferably, if the synchronized access to the third basestation by the user equipment fails, the user equipment notifies thefirst base station, the first base station stops forwarding data to thethird base station, and the first base station notifies the second basestation and the third base station after completing a third admissioncontrol so that data of a third radio bearer acceptable by the firstbase station in the first radio bearer is forwarded to the first basestation and a radio bearer unacceptable by the first base station in thefirst radio bearer is released, and notifies the user equipment torelease the radio bearer unacceptable by the first base station in thefirst radio bearer at the same time.

Further, preferably, if data of the third base station is directlyrouted from a core network after completing triggering of the transferprocedure and the synchronized access to the third base station by theuser equipment succeeds, the third base station further notifies thecore network to modify a core network bearer corresponding to the firstradio bearer acceptable by the third base station so that data of thefirst radio bearer is directly routed to the third base station.

According to another preferred embodiment of the invention, if data ofthe first base station is forwarded via the second base station, thesecond base station performs data forwarding operation to forward dataof the first radio bearer acceptable by the third base station to thethird base station according to the result of the first admissioncontrol, and performs data forwarding operation to forward data of thesecond radio bearer acceptable by the first base station to the firstbase station according to the result of the second admission control.

Preferably, if synchronized access to the third base station by the userequipment succeeds, the third base station triggers a core network toperform path switch so that data sent to the second base station fromthe core network is directly routed to the third base station, the thirdbase station starts forwarding data of a downlink bearer transmitted viathe first base station to the first base station after completing thepath switch, and the second base station releases information relatingto the user equipment and its services after completing data forwardingoperation.

Further, preferably, if synchronized access to the third base station bythe user equipment fails, the user equipment notifies the first basestation, the first base station notifies the second base station and thethird base station after a third admission control so that data of athird radio bearer acceptable by the first base station in the firstradio bearer and data of original services of the first base station isforward to the first base station via the second base station, andnotifies the user equipment at the same time, and the second basestation stops forwarding data to the third base station after acquiringthat the synchronized access fails.

Further, preferably, if the synchronized access to the third basestation by the user equipment fails, after completing the thirdadmission control by the first base station, the first base station orthe second base station notifies the core network to switch a path fordata forwarded to the first base station via the second base station tothe first base station and release a core network bearer correspondingto a radio bearer unacceptable by the first base station in the firstradio bearer, and notifies the user equipment to release the radiobearer unacceptable by the first base station in the first radio bearerat the same time.

According to another aspect of the invention, there is provided a methodused in a wireless communication system, the wireless communicationsystem including a first base station, a second base station, a thirdbase station and user equipment, wherein the first base station and thesecond base station perform wireless data connection with the userequipment over different carriers, the method including: a judging stepof judging, by a triggering node, whether a predetermined transfercondition for transferring services provided to the user equipment bythe second base station to the third base station is satisfied; and atriggering step of triggering the transfer procedure if it is judgedthat the predetermined transfer condition is satisfied, so that the userequipment releases wireless data connection with the second base stationand establishes wireless data connection with the third base station,and thus the first base station and the third base station performwireless data connection with the user equipment over differentcarriers, wherein at least part of the services originally provided bythe second base station is transferred to the third base station.

According to another aspect of the invention, there is also provided astorage medium including machine readable program codes which whenexecuted on an information processing apparatus, cause the informationprocessing apparatus to perform the following steps: a judging step ofjudging, by a triggering node, whether a predetermined transfercondition for transferring services provided to user equipment by asecond base station to a third base station is satisfied, and atriggering step of triggering the transfer procedure if it is judgedthat the predetermined transfer condition is satisfied, so that the userequipment releases wireless data connection with the second base stationand establishes wireless data connection with the third base station,and thus a first base station and the third base station performwireless data connection with the user equipment over differentcarriers, wherein at least part of the services originally provided bythe second base station is transferred to the third base station.Particularly, the first base station, the second base station, the thirdbase station and the user equipment are included in a wirelesscommunication system, and the first base station and the second basestation perform wireless data connection with the user equipment overdifferent carriers.

According to another aspect of the invention, there is also provided aprogram product including machine executable instructions which whenexecuted on an information processing apparatus cause the informationprocessing apparatus to perform the following steps: a judging step ofjudging, by a triggering node, whether a predetermined transfercondition for transferring services provided to user equipment by asecond base station to a third base station is satisfied; and atriggering step of triggering the transfer procedure if it is judgedthat the predetermined transfer condition is satisfied, so that the userequipment releases wireless data connection with the second base stationand establishes wireless data connection with the third base station,and thus a first base station and the third base station performwireless data connection with the user equipment over differentcarriers, wherein at least part of the services originally provided bythe second base station is transferred to the third base station.Particularly, the first base station, the second base station, the thirdbase station and the user equipment are included in a wirelesscommunication system, and the first base station and the second basestation perform wireless data connection with the user equipment overdifferent carriers.

Other aspects of the embodiments of the disclosure will be presented inthe following detailed description serving to fully disclose preferredembodiments of the disclosure but not to limit the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be better understood with reference to the detaileddescription given below in conjunction with the accompanying drawings,throughout which identical or like reference signs denote identical orlike components. The accompanying drawings together with the followingdetailed description are incorporated into and form a part of thespecification and serve to further illustrate the preferred embodimentsof the disclosure and to explain the principle and advantages of thedisclosure by way of example. In the drawings:

FIG. 1 is a schematic block diagram illustrating a wirelesscommunication system according to an embodiment of the disclosure;

FIG. 2 is a schematic diagram illustrating an exemplary scene in which afirst base station serves as a triggering node to trigger a transferprocedure according to an embodiment of the disclosure;

FIG. 3 is a schematic diagram illustrating an exemplary scene in which asecond base station serves as a triggering node to trigger a transferprocedure according to an embodiment of the disclosure;

FIG. 4 is a schematic diagram illustrating an exemplary scene in a casethat data of first, second and third base stations is directly routedfrom a core network before triggering a transfer procedure and aftercompleting triggering of the transfer procedure and synchronized accessto the third base station by user equipment succeeds according to anembodiment of the disclosure;

FIG. 5 is a schematic diagram illustrating an exemplary scene in a casethat data of a second base station comes directly from a core networkand synchronized access to a third base station by user equipment failsaccording to an embodiment of the disclosure;

FIG. 6A is a schematic diagram illustrating an exemplary scene in a casethat data of a second base station and a third base station is forwardedvia a first base station and synchronized access to the third basestation by user equipment succeeds according to an embodiment of thedisclosure;

FIG. 6B is a schematic diagram illustrating another exemplary scene in acase that data of a second base station and a third base station isforwarded via the first base station and synchronized access to thethird base station by user equipment succeeds according to an embodimentof the disclosure;

FIG. 6C is a schematic diagram illustrating an exemplary scene in a casethat data of a second base station is forwarded via the first stationwhile data of a third base station is directly routed from the corenetwork after completing triggering of a transfer procedure andsynchronized access to the third base station by user equipment succeedsaccording to an embodiment of the disclosure;

FIG. 7 is a schematic diagram illustrating an exemplary scene in a casethat data of a second base station is forwarded via a first base stationand synchronized access to a third base station by user equipment failsaccording to an embodiment of the disclosure;

FIG. 8 is a schematic diagram illustrating an exemplary scene in a casethat data of a first base station is forwarded via a second base stationand synchronized access to a third base station by user equipmentsucceeds according to an embodiment of the disclosure;

FIG. 9 is a schematic diagram illustrating an exemplary scene in a casethat data of a first base station is forwarded via a second base stationand synchronized access to a third base station by user equipment failsaccording to an embodiment of the disclosure;

FIG. 10 is a block diagram illustrating an example of functionalconfiguration of a first base station serving as a connectionmaintaining node according to an embodiment of the disclosure;

FIG. 11 is a block diagram illustrating an example of functionalconfiguration of a first base station serving as a connectionmaintaining node according to another embodiment of the disclosure;

FIG. 12 is a block diagram illustrating an example of functionalconfiguration of a second base station serving as a connection transfersource node according to an embodiment of the disclosure;

FIG. 13 is a block diagram illustrating an example of functionalconfiguration of a second base station serving as a connection transfersource node according to another embodiment of the disclosure;

FIG. 14 is a block diagram illustrating an example of functionalconfiguration of a third base station serving as a connection transfertarget node according to an embodiment of the disclosure;

FIG. 15 is a block diagram illustrating an example of functionalconfiguration of user equipment according to an embodiment of thedisclosure;

FIG. 16 is a flow chart illustrating an example of a procedure of amethod used in the wireless communication system according to anembodiment of the disclosure; and

FIG. 17 is a block diagram illustrating an exemplary structure of apersonal computer as an information processing apparatus that may beused in an embodiment of the disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present disclosure will be described belowin conjunction with the accompanying drawings. For the sake of clarityand conciseness, not all the features of practical implementations aredescribed in the specification. However, it is to be appreciated thatnumerous implementation-specific decisions shall be made duringdeveloping any of such practical implementations so as to achieve thedeveloper's specific goals, for example, to comply with system- andservice-related constraining conditions which will vary from oneimplementation to another. Moreover, it shall also be appreciated thatsuch a development effort might be very complex and time-consuming butmay simply be a routine task for those skilled in the art benefitingfrom this disclosure.

It shall further be noted that only those device structures and/orprocess steps closely relevant to the solutions of the disclosure areillustrated in the drawings while other details less relevant to thedisclosure are omitted so as not to obscure the disclosure due to thoseunnecessary details.

Embodiments of the disclosure will be described with reference to FIGS.1-17 below. First, an example of a wireless communication systemaccording to an embodiment of the disclosure will be described withreference to FIG. 1. FIG. 1 is a schematic block diagram illustrating awireless communication system according to an embodiment of thedisclosure.

As shown in FIG. 1, the wireless communication system 100 according tothe embodiment of the disclosure may include a first base station 102, asecond base station 104, a third base station 106 and user equipment108. Particularly, the first base station 102 and the second basestation 104 perform wireless data connection with the user equipment 108over different carriers, and a triggering node triggers a transferprocedure if it judges a predetermined transfer condition fortransferring services provided to the user equipment 108 by the secondbase station 104 to the third base station 106 is satisfied, so that theuser equipment 108 releases wireless data connection with the secondbase station 104 and establishes wireless data connection with the thirdbase station 106, and thus the first base station 102 and the third basestation 106 perform wireless data connection with the user equipment 108over different carriers, and at least part of the services originallyprovided by the second base station 104 is transferred to the third basestation 106.

The predetermined transfer condition under which the services providedto the user equipment 108 by the second base station 104 is transferredto the third base station 106 includes one or more of the followingfactors: service quality of the third base station 106 is higher thanservice quality of the second base station 104 by a predeterminedthreshold; the service quality of the third base station 106 is higherthan a predetermined threshold; the service quality of the second basestation 104 is lower than a first predetermined threshold and theservice quality of the third base station 106 is higher than a secondpredetermined threshold; and so on. It is to be understood that theabove predetermined transfer condition has been described assuming thatan object to be transferred has been determined among the first basestation 102 and the second base station 104.

On the other hand, when both base stations which perform wireless dataconnection with the user equipment over different carriers satisfy thepredetermined transfer condition at the same time, in a case that it hasnot been determined which base station is to be transferred first (thatis, during a two-step transfer procedure, which base station is thefirst base station 102, which base station is the second base station104 and which base station is the third base station 106), as analternative example, the above described predetermined transfercondition may further include for example the service quality of onebase station is higher than that of another base station.

Preferably, when determining the object to be transferred among theabove two base stations, measurement results regarding serving carriersof these two base stations should be reported to the triggering node,then the triggering node will determine the transfer procedure withrespect to which base station is to be started first based on a type ofthe base station (for example, master node/slave node, macro basestation/low power node, and the like), channel quality or load conditionor the like. As an alternative example, if the channel quality of onebase station is lower than a predetermined threshold and approximatesfailure while another base station is looking for a better neighbor,then a base station with poorest channel quality is determined as theobject to be transferred, and the transfer procedure with respect tothis base station is started first. As another alternative example, iftwo base stations have substantially the same channel quality, then abase station with heavier load will be determined as the object to betransferred, and the transfer procedure with respect to this basestation is started first.

Further, preferably, in a case that all of the services originallyprovided by the second base station 104 can not be transferred to thethird base station 106, the transfer procedure further causes part ofthe services originally provided by the second base station 104 to betransferred to the first base station 102. It is to be noted thatalthough FIG. 1 shows only one first base station 102, the number of thefirst base station 102 is not limited thereto, and the first basestation 102 may be a set of base stations including a plurality of firstbase stations, for example, a plurality of coordinated base stations inJoint Processing technology, and thus during the above transferprocedure, part of the services originally provided by the second basestation 104 may be transferred to one or more first base stations in theset of base stations. Further, in this case, the service quality of theplurality of first base stations is measured in a cell unit, forexample, in case of Coordinated Multiple Point (CoMP) transmission, theservice quality of multiple coordinated base stations may be measured byregarding a carrier coordinated by the multiple base stations as onecell.

Further, it is to be understood that during the above transferprocedure, the first base station 102 always maintains the wireless dataconnection with the user equipment, the services provided by the secondbase station 104 is transferred, and at least part of the servicesoriginally provided by the second base station 104 is transferred to thethird base station 106, and thus in some embodiments of the invention,the first base station 102 may be also referred to as a connectionmaintaining node, the second base station 104 may be also referred to asa connection transfer source node, and the third base station 106 may bealso referred to as a connection transfer target node. The abovedescribed triggering node may be one serving node to which the userequipment 108 is connected currently, for example, may be the first basestation 102 as the connection maintaining node, and may be also thesecond base station 104 as the connection transfer source node.

Further, it is to be understood that the terms “first”, “second” and“third” used herein are only used for distinguishing to facilitatedescription but not limitation, for example, when the first base station102 conforms to characteristics of the connection transfer source nodeor the connection transfer target node, the first base station 102 canof course be the connection transfer source node or the connectiontransfer target node, and this also applies to the second base station104 and the third base station 106.

Specifically, in a case that the triggering node judges thepredetermined transfer condition is satisfied according to mobilitymeasurement result regarding serving carriers of at least the secondbase station 104 and optionally the first base station 102 and the thirdbase station 106, the triggering node sends a transfer requestcontaining relevant information of the first base station and the secondbase station to the third base station 106, and the third base station106 performs a first admission control according to the transfer requestand sends a transfer response to notify a result of the first admissioncontrol. Particularly, the third base station 106 may return thetransfer response directly to the triggering node, or may send thetransfer response to another serving node connected with the userequipment 108.

Preferably, the transfer response may include for which part of radiobearer of the user equipment 108 that the third base station 108 canperform communication, a dedicated preamble code as required when makingsynchronized access to the third base station 106, system informationabout a carrier for communication between the user equipment 108 and thethird base station 106 and configuration information about a controlplane protocol for establishing communication between the user equipment108 and the third base station 106.

Preferably, if the result of the first admission control indicates thatthe third base station 106 can not accept all the radio bearers betweenthe user equipment 108 and the second base station 104, then accordingto the transfer response of the third base station 106 (the transferresponse directly received from the third base station 106 or thetransfer response of the third base station 106 forwarded to the firstbase station 102 via the second base station 104), the first basestation 102 performs a second admission control according to the resultof the first admission control and notifies a result of the secondadmission control to the second base station 104.

Further, preferably, the first base station 102 or the second basestation 104 sends, after acquiring the final result of the firstadmission control or the second admission control, a notificationmessage to the user equipment 108 to notify the user equipment 108 toperform the transfer procedure according to the final result and thetransfer response of the third base station 106. The notificationmessage includes at least one of: for which part of radio bearer of theuser equipment that the first base station 102 can performcommunication, for which part of radio bearer of the user equipment 108that the third base station 106 can perform communication, a dedicatedpreamble code as required when making synchronized access to the thirdbase station 106, system information about a carrier for communicationbetween the user equipment 108 and the third base station 106 andconfiguration information about a control plane protocol forestablishing communication between the user equipment 108 and the thirdbase station 106. Also, the user equipment 108 releases radio bearerswhich can not be accepted by the first base station 102 and the thirdbase station 106 after receiving the notification message, releases thewireless data connection with the second base station 104 and performssynchronized access operation to the third base station 106.

Further, preferably, the above described triggering node may be thefirst base station 102 or the second base station 104.

Examples of scenes of the transfer procedure in cases that the firstbase station 102 and the second base station 104 serve as the triggeringnode respectively will be described with reference to FIGS. 2 and 3below. FIG. 2 is a schematic diagram illustrating an exemplary scene inwhich the first base station serves as the triggering node to triggerthe transfer procedure according to an embodiment of the disclosure, andFIG. 3 is a schematic diagram illustrating an exemplary scene in whichthe second base station serves as the triggering node to trigger thetransfer procedure according to an embodiment of the disclosure.

As shown in FIG. 2, in a case that the first base station 102 serves asthe triggering node, the user equipment 108 may send the mobilitymeasurement result to the second base station 104, and the second basestation 104 forwards the mobility measurement result to the first basestation 102 as shown by solid-line arrows in FIG. 2 as reference for thefirst base station 102 to trigger the transfer procedure. An advantageof this example lies in reducing modifications to the existing standard(the user equipment directly reports to a serving base station themobility carrier measurement result of the serving base station).Further, the user equipment 108 may also send the mobility measurementresult regarding a serving carrier (containing at least a primarycarrier) of the second base station 104 to the first base station 102 in“measurement report” for example, as shown by a broken-line arrow inFIG. 2. An advantage of this example lies in that the user equipment 108may directly send the measurement report regarding the serving carrierof the second base station 104 to the first base station 102, therebysaving information interaction between the second base station 104 andthe first base station 102.

Next, the first base station 102 may send a transfer request to thethird base station 106 in “transfer request” for example after judgingthe above predetermined transfer condition is satisfied according to thereceived information of the mobility measurement result, then the thirdbase station 104 performs the first admission control according to thetransfer request, and sends a response to the transfer request to thefirst base station 102 in “transfer response” for example so as tonotify the result of the first admission control to the first basestation 102. The result of the first admission control indicates whetherthe third base station 106 can accept all the radio bearers between theuser equipment 108 and the second base station 104 or which part of theradio bearers can be accepted by the third base station 106.

Thereafter, the first base station 102 or the third base station 106notifies the result of the first admission control to the second basestation 104 in “transfer notification” for example, and the first basestation 102 or the second base station 104 notifies the user equipment108 to perform the transfer procedure in “transfer confirmation” forexample according to the result and the transfer response of the thirdbase station 106. The specific contents contained in the notificationmessage “transfer confirmation” have been described above, and norepeated description will be made herein.

Preferably, if the result of the first admission control performed bythe third base station 106 indicates that the third base station 106 cannot accept all the radio bearers between the user equipment 108 and thesecond base station 104, the first base station 102 may perform thesecond admission control according to the result of the first admissioncontrol contained in the received “transfer response”, as shown bybroken-line block in FIG. 2. It is to be understood that by performingthe second admission control by the first base station 102 to transferat least part of the radio bearers that can not be accepted by the thirdbase station 106 to the first base station 102, it is possible tofurther ensure the user equipment 108 obtains excellent service quality.This is merely a preferred example of course but not limitation, and itis also possible to directly notify the user equipment 108 to releasethe services unacceptable by the third base station 108 after performingthe first admission control, without performing the second admissioncontrol by the first base station 102. After judging through the firstadmission control and/or the second admission control, the second basestation 104 releases the radio bearers which are originally transmittedby the second base station 104 and which can not be accepted by thethird base station 106 and the first base station 102, and notifies thecore network to release core network bearers corresponding to the radiobearers.

It is to be noted that in this case, the first base station 102 maynotify the final result about the first admission control and the secondadmission control to the second base station 104 in “transfernotification” for example after performing the second admission control,then the first base station 102 or the second base station 104 notifiesthe final result to the user equipment 108 in “transfer confirmation”for example, and thus the radio bearer acceptable by the third basestation can be transferred to the third base station 106 and the radiobearer acceptable by the first base station 102 can be transferred tothe first base station 102.

After receiving the above notification message “transfer confirmation”,the user equipment 108 releases the services that can not be accepted bythe first base station 102 and the third base station 106, releases thewireless data connection with the second base station 104 and performsthe synchronized access operation to the third base station 106.

A basic signaling flow of the transfer procedure in a case that thefirst base station 102 serves as the triggering node has been describedin detail with reference to FIG. 2 above, and next, an example of ascene of the transfer procedure in a case that the second base station104 serves as the triggering node will be described in detail withreference to FIG. 3.

As shown in FIG. 3, since the triggering node is the second base station104 at this time, the user equipment 108 only needs to notify thecarrier mobility measurement result to the second base station 104, andthe second base station 104 sends the transfer request to the third basestation 106 after judging the predetermined transfer condition issatisfied according to the measurement result so as to trigger thetransfer procedure. Then, the third base station 106 sends to the secondbase station 104 a response message “transfer response” for the transferrequest after performing the first admission control, so as to notifythe result of the first admission control to the second base station104. Next, the second base station 104 or the third base station 106 maynotify the result to the first base station 102, and the second basestation 104 sends the notification message to the user equipment 108 in“transfer confirmation” according to the received “transfer response”.

Preferably, similar to the case described in FIG. 2, the first basestation 102 may also perform the second admission control according tothe received result of the first admission control. Specifically, whenthe “transfer response” of the third base station 106 received by thesecond base station 104 indicates that the third base station 106 cannot accept all the radio bearers between the user equipment 108 and thesecond base station 104, the second base station 104 sends “transferrequest” to the first base station 102 with respect to the radio bearersthat can not be by the third base station 106, the first base station102 performs the second admission control according to the “transferrequest” and notifies the final result of the admission control to thesecond base station 104 in “transfer response” for example. Then, thesecond base station 104 sends a notification to the user equipment 108according to the final result. In this example, the “transfer response”sent by the first base station includes for which part of the radiobearers of the user equipment that the first base station 102 canperform communication.

As can be seen from comparison of FIGS. 2 and 3, the transfer proceduresin these two cases are similar to each other, and the difference onlylies in that the base stations serving as the triggering node aredifferent, thereby leading to differences in transmitting and receivingnodes and timings for some signaling. Therefore, parts which are notdescribed in detail in FIG. 3 can be referred to FIG. 2, and no repeateddescription will be made herein.

Examples of scenes for basic signaling interactions of the transferprocedure in different cases have been described in detail withreference to FIGS. 2 and 3, and examples of scenes for data forwardingand path switch among network nodes in different cases after the basicsignaling interaction of the transfer procedure will be described indetail with reference to FIGS. 4-9 below.

FIG. 4 is a schematic diagram illustrating an exemplary scene in a casethat the data of the first, second and third base stations is directlyrouted from the core network before triggering the transfer procedureand after completing triggering of the transfer procedure andsynchronized access to the third base station by the user equipmentsucceeds according to an embodiment of the disclosure.

Specifically, if the data of the first base station 102, the second basestation 104 and the third base stations 106 is directly routed from thecore network before triggering the transfer procedure and aftercompleting triggering of the transfer procedure, the second base station104 performs data forwarding operation to forward data of a first radiobearer acceptable by the third base station 106 to the third basestation 106 according to the result of the first admission control, andfurther performs data forwarding operation to forward data of a secondradio bearer acceptable by the first base station 102 to the first basestation 102 according to the result of the second admission control, andthe first base station 102 or the second base station 104 notifies thecore network to switch a path corresponding to the second radio bearerto the first base station 102.

It is to be noted that if the result of the first admission controlindicates that the third base station 106 can accept all the radiobearers, then only data of the first radio bearer accepted by the thirdbase station 106 is needed to be forwarded to the third base station106, otherwise, data of the second radio bearer accepted by the firstbase station 102 also needs to be forwarded to the first base station102 at the same time.

After the data forwarding operation, as shown in FIG. 4, if thesynchronized access to the third base station 106 by the user equipment108 succeeds, the third base station 106 notifies the core network toswitch a path corresponding to the first radio bearer to the third basestation 106. Specifically, the third base station 106 may send “pathswitch request” for example to a mobility management entity (MME). Afterreceiving the request, the mobility management entity sends “bearermodifying request” for example to a gateway, and after receiving therequest, the gateway performs switching downlink path operation and thusthe data of the first radio bearer acceptable by the third base station106 is directly routed to the third base station 106, and the gatewaysends to the second base station 104 an end flag to inform a number of alast data packet forwarded to the third base station 106 via the secondbase station 104. Thereafter, the gateway sends “bearer modifyingresponse” for example to the mobility management entity, and meanwhile,after receiving the response, the mobility management entity sends “pathswitch confirmation” for example as confirmation for the path switchrequest. Then, the third base station 106 may notify the second basestation 104 to release relevant user equipment information, and thesecond base station 104 may release the resources related to the userequipment 108 and services thereof after receiving the notification.

Otherwise, as shown in FIG. 5, if the synchronized access to the thirdbase station 106 by the user equipment 108 fails, the user equipment 108will notify the first base station 102, and the first base station 102performs a third admission control to perform admission control on thefirst radio bearer and notifies the second base station 104 and thethird base station 106 after the third admission control, to notify thefailure of the synchronized access and cause data of a third radiobearer acceptable by the first base station 102 in the first radiobearer to be forwarded to the first base station 102. The first basestation 102 also notifies the core network to switch a pathcorresponding to the third radio bearer to the first base station 102.Meanwhile, the first base station 102 notifies the user equipment 108 ofwhich data can be transmitted over carriers of the first base station102 and which data needs to be released, notifies the second basestation 104 and the third base station 106 of which radio bearers shouldbe released and notifies the core network to release core networkbearers corresponding to the radio bearers.

It is to be noted that in a case that the synchronized access fails, asshown in FIG. 5, except that the mobility management entity is notifiedby the first base station 102 at this time, specific path switchoperations related to the core network end are similar to the procedureas described above with reference to FIG. 4, and thus, no repeateddescription will be made herein.

As can be seen from the above description with reference to FIGS. 4 and5, for the second radio bearer determined according to the result of thesecond admission control performed by the first base station 102,irrespective of success or failure of the synchronized access to thethird base station 106 by the user equipment 108, the core network isnotified to switch corresponding path to the first base station 102. Asfor the first radio bearer determined according to the result of thefirst admission control performed by the third base station 106, only ifthe synchronized access to the third base station 106 by the userequipment 108 succeeds, the core network is notified to switch pathcorresponding to the first radio bearer to the third base station 106,and if the synchronized access fails, the first base station 102performs the third admission control for the first radio bearer andnotifies the core network to switch path corresponding to the thirdradio bearer determined according to the result of the third admissioncontrol to the first base station 102. That is to say, for the servicescorresponding to the second radio bearer and the third radio bearerwhich are originally provided by the second base station 104, the firstbase station 102 provides these services at this time. Further, in acase that the synchronized access fails, it also needs to notify theuser equipment 108 that the third radio bearer should be transferred tothe first base station 102 for transmission and to notify the userequipment 108 to release the radio bearers unacceptable by the firstbase station 102 after the third admission control.

Next, exemplary scenes in a case that the data of the second basestation 104 is forwarded via the first base station 102 will bedescribed with reference to FIGS. 6A, 6B, 6C and 7. FIG. 6A is aschematic diagram illustrating an exemplary scene in a case that thedata of the second base station and the third base station is forwardedvia the first base station and the synchronized access to the third basestation by the user equipment succeeds according to an embodiment of thedisclosure; FIG. 6B is a schematic diagram illustrating anotherexemplary scene in a case that the data of the second base station andthe third base station is forwarded via the first base station and thesynchronized access to the third base station by the user equipmentsucceeds according to an embodiment of the disclosure; FIG. 6C is aschematic diagram illustrating an exemplary scene in a case that thedata of the second base station is forwarded via the first station whilethe data of the third base station is directly routed from the corenetwork after completing triggering of the transfer procedure and thesynchronized access to the third base station by the user equipmentsucceeds according to an embodiment of the disclosure; and FIG. 7 is aschematic diagram illustrating an exemplary scene in a case that thedata of the second base station is forwarded via the first base stationand the synchronized access to the third base station by the userequipment fails according to an embodiment of the disclosure.

Specifically, if the data of the second base station 104 and the thirdbase station 106 is forwarded from the first base station 102, the firstbase station 102 stops forwarding data to the second base station 104after completing confirmation for the first admission control orcompleting the second admission control, and the second base station 104performs data forwarding operation according to the result of the firstadmission control to forward the data of the first radio beareracceptable by the third base station 106 to the third base station 106and also performs data forwarding operation according to the result ofthe second admission control to forward the data of the second radiobearer acceptable by the first base station 102 to the first basestation 102.

At this time, the data of the second base station 104 is forwarded fromthe first base station 102, and thus the first base station 102 alsoneeds to perform data forwarding operation for the third base station106, and the first base station 102 may perform, after completingconfirmation for the first admission control, the data forwardingoperation simultaneously with the second base station 104 so as toforward the data of the first radio bearer to the third base station 106regardless of success or failure of the synchronized access between theuser equipment 108 and the third base station 106, as shown in FIG. 6A.Alternatively, the first base station 102 may also perform dataforwarding operation only after acquiring the success of thesynchronized access between the user equipment 108 and the third basestation 106, as shown in FIG. 6B, which is more suitable for a situationin which the first base station 102 and the second base station 104transmit services for one same radio bearer at the same time.

Further, the second base station 104 automatically releases resourcesrelated to the services of the user equipment 108 after completing thedata forwarding operation.

Particularly, if the result of the first admission control indicatesthat the third base station 106 can not accept all the radio bearers,while the data forwarding operation for the first radio bearer acceptedby the third base station 106 is performed, in addition to stoppingforwarding data to the second base station 104 by the first base station102, the second base station 104 also needs to transfer the data of thesecond radio bearer accepted by the first base station 102 back to thefirst base station 102 for transmission.

Alternatively, as shown in FIG. 6C, if the data of the second basestation 104 is forwarded from the first base station 102 while the dataof the third base station 106 is directly routed from the core networkafter completing triggering of the transfer procedure, in a case thatthe synchronized access to the third base station 106 by the userequipment 108 succeeds, in addition to the processing proceduresdescribed above with reference to FIGS. 6A and 6B, operations at thecore network end are also involved, that is, the third base station 106needs to notify the core network to modify the core network bearercorresponding to the first radio bearer acceptable by the third basestation 106. Specifically, after the synchronized access to the thirdbase station 106 by the user equipment 108 succeeds, the third basestation 106 further sends “path switch request” for example to themobility management entity, the mobility management entity sends, afterreceiving the request, “bearer modifying request” for example to thegateway, and the gateway performs switching downlink path operationafter receiving the request and thus the data of the first radio beareracceptable by the third base station 106 is directly routed to the thirdbase station 106, and the gateway sends an end flag to the first basestation 102 to inform the number of the last data packet forwarded tothe third base station 106 via the first base station. Thereafter, thegateway sends “bearer modifying response” for example to the mobilitymanagement entity, and the mobility management entity sends, afterreceiving the response, “path switch confirmation” for example asconfirmation for the “path switch request” to the third base station106, thereby notifying the third base station 106 of completion of thepath switch operation at the core network end.

However, if the synchronized access to the third base station 106 by theuser equipment 108 fails, as shown in FIG. 7, similar to the scenedescribed with reference to FIG. 5, the user equipment 108 firstnotifies the first base station 102, the first base station 102 stopsforwarding data to the third base station 106 after receiving thenotification, and the first base station 102 notifies the second basestation 104 and the third base station 106 after performing the thirdadmission control to notify the failure of the synchronized access andcause the second base station 104 and the third base station 106 toperform data forwarding operation for the third radio bearer acceptableby the first base station 102 in the first radio bearer, so that thedata of the third radio bearer acceptable by the first base station 102in the first radio bearer is forwarded to the first base station 102 andthe radio bearer unacceptable by the first base station 102 in the firstradio bearer is released. Meanwhile, the first base station 102 notifiesthe user equipment 108 of which data can be transmitted over carriers ofthe first base station 102 and which data needs to be released.

As can be seen from above description with reference to FIGS. 6A, 6B and7, under these scenes, the first base station 102 is responsible forforwarding data to other base stations in the wireless communicationsystem, and thus, no path switch operation at the core network end willbe involved in both cases of success and failure of the synchronizedaccess operation.

Further, it is to be noted that although FIG. 7 shows that the firstbase station 102 and the second base station 104 performs dataforwarding operation for the third base station 106 at the same time,but this is merely an example, and similar to FIG. 6B, the first basestation 102 may also not perform data forwarding operation for the thirdbase station 106 at first, which is not limited herein.

Exemplary scenes in a case that the data of the first base station isforwarded via the second base station will be described with referenceto FIGS. 8 and 9 below. FIG. 8 is a schematic diagram illustrating anexemplary scene in a case that the data of the first base station isforwarded via the second base station and the synchronized access to thethird base station by the user equipment succeeds according to anembodiment of the disclosure; and FIG. 9 is a schematic diagramillustrating an exemplary scene in a case that the data of the firstbase station is forwarded via the second base station and thesynchronized access to the third base station by the user equipmentfails according to an embodiment of the disclosure.

Specifically, if the data of the first base station 102 is forwarded viathe second base station 104, the second base station 104 performs dataforwarding operation according to the result of the first admissioncontrol to forward the data of the first radio bearer acceptable by thethird base station 106 to the third base station 106, and performs dataforwarding operation according to the result of the second admissioncontrol to forward the data of the second radio bearer acceptable by thefirst base station 102 to the first base station 102.

If the synchronized access to the third base station 106 by the userequipment 108 succeeds, as shown in FIG. 8, the third base station 106triggers the core network to perform path switch to route the data sentfrom the core network to the second base station 104 directly to thethird base station 106, and after completing the path switch, the thirdbase station 106 starts forwarding the data of downlink bearertransmitted via the first base station 102 to the first base station102, and the second base station 104 releases information related to theuser equipment and services thereof after completing the data forwardingoperation. Specifically, after succeeding in the synchronized access,the third base station 106 sends “path switch request” for example tothe mobility management entity, the mobility management entity sends,after receiving the request, “bearer modifying request” for example tothe gateway, and the gateway performs switching downlink path operationafter receiving the request and thus the data of the first radio beareracceptable by the third base station 106 is directly routed to the thirdbase station 106, and the gateway sends an end flag to the second basestation 104. Then, the second base station 104 forwards this end flag tothe first base station 102 to inform the first base station of thenumber of last data packet forwarded via the second base station 104.Thereafter, the gateway sends “bearer modifying response” for example tothe mobility management entity, and the mobility management entity sends“path switch confirmation” for example as confirmation for the “pathswitch request” to the third base station 106 after receiving theresponse, and thus notifies the third base station 106 that the pathswitch operation at the core network end has been completed.

As can be seen from FIG. 8, in a case that the synchronized accesssucceeds, after receiving the end flag for the services transmitted bythe first base station 102, the second base station 104 forwards theflag to the first base station 102, and then releases all resourcesrelated to the user equipment 108 after receiving a message “userequipment information release” sent by the third base station 106 and/orthe first base station 102.

Otherwise, if the synchronized access to the third base station 106 bythe user equipment 108 fails, then as shown in FIG. 9, the userequipment 108 notifies the first base station 102, and the first basestation 102 notifies the second base station 104 and the third basestation 106 after performing the third admission control to notify thefailure of the synchronized access and cause the second base station 104and the third base station 106 perform data forwarding operation for thethird radio bearer acceptable by the first base station 102 in the firstradio bearer, and meanwhile notifies the user equipment 108 of whichdata can be transmitted over carriers of the first base station 102 andwhich data needs to be released.

Preferably, in the case that the synchronized access fails, the data ofthe services transmitted by the first base station 102 (that is, data ofthe original services of the first base station 102, data of the secondradio bearer and data of the third radio bearer) may also be forwardedto the first base station 102 via the second base station 104. In thiscase, when switching needs to be performed among small base stations,there always exists one anchor base station (for example, the secondbase station 104 herein) being responsible for data forwarding, and thusit only needs to notify the anchor base station of the transfer the dataforwarding.

However, alternatively, it is also possible that after completing thethird admission control by the first base station 102, the first basestation 102 or the second base station 104 notifies the core network toperform path switch for the data of all the radio bearers accepted bythe first base station 102, so that the path corresponding to the dataforwarded to the first base station 102 via the second base station 104is switched to the first base station 102 and the core network bearercorresponding to the radio bearer unacceptable by the first base station102 in the first radio bearer is released, and meanwhile notifies theuser equipment 108 to release the radio bearer unacceptable by the firstbase station 102 in the first radio bearer.

It is to be noted that in the case that the synchronized access fails,as shown in FIG. 9, except that the mobility management entity isnotified by the first base station 102 or the second base station 104 atthis time, specific path switch operations involving the core networkare similar to those described above with reference to FIG. 8, and thusno repeated description will be made herein.

Although data forwarding and path switch operations after the transferprocedure in various situations have been described above with referenceto FIGS. 4-9, it should be understood that the drawings and relateddescription thereof are only examples but not limitation, and thoseskilled in the art may modify the above procedures according to theprinciple of the invention. For example, although in the above the firstbase station 102 and the third base station 106 together undertake atleast part of the services originally provided by the second basestation 104, it is also possible that the third base station 106undertakes this individually, while for the services unacceptable by thethird base station 106, the user equipment 108 is notified to releasethis part of the services. Further, although it only shows the secondbase station 104 performs data forwarding operation to the third basestation 106 in FIGS. 4-9, this is merely for the purpose of clarity ofillustration but not limitation, it should be understood that in a casethat the first base station 102 performs admission control, the secondbase station 104 also performs data forwarding operation to the firstbase station 102 with respect to the radio bearer accepted by the firstbase station 102.

Further, it should be noted that for the purpose of clarity, onlysignaling interactions closely related to the disclosure are shown inthe drawings, and for other well-known signaling interactions in theart, no detailed description will be made herein.

As can be understood from the above detailed description of theembodiments of the disclosure, by performing the above transferprocedure in the case that the predetermined transfer condition issatisfied, it is possible to ensure the user equipment obtains optimizedservice quality while improving data transmission efficiency.

An example of functional configuration of a first base station servingas the connection maintaining node according to an embodiment of thedisclosure will be described with reference to FIG. 10 below. FIG. 10 isa block diagram illustrating an example of functional configuration of afirst base station serving as the connection maintaining node accordingto an embodiment of the disclosure.

As shown in FIG. 10, the first base station 1000 according to thepresent embodiment may include a measurement result receiving unit 1002,a judging unit 1004, a transfer request sending unit 1006 and a transferresponse receiving unit 1008. Examples of functional configurations ofrespective units will be described in detail below.

The measurement result receiving unit 1002 may be configured to receive,in a case that the first base station 1000 is the triggering node totrigger the above transfer procedure, a mobility measurement resultregarding the serving carrier between the user equipment and the secondbase station from the user equipment or the second base station as theconnection transfer source node.

The judging unit 1004 may be configured to judge whether thepredetermined transfer condition of transferring the services providedto the user equipment by the second base station to the third basestation is satisfied based on the mobility measurement result receivedby the measurement result receiving unit 1002.

The transfer request sending unit 1006 may be configured to send atransfer request to the third base station as the connection transfertarget node in a case that the judging unit 1004 judges thepredetermined transfer condition is satisfied, so as to trigger the userequipment to release the wireless data connection with the second basestation and establish the wireless data connection with the third basestation, and thus the first base station and the third base stationperform wireless data connection with the user equipment over differentcarriers. Particularly, at least part of the services originallyprovided by the second base station is transferred to the third basestation.

The transfer response receiving unit 1008 may be configured to receivefrom the third base station the transfer response which may include theresult of the admission control performed by the third base station.

Preferably, the first base station 1000 may further include a firstadmission control performing unit 1010. The first admission controlperforming unit 1010 may be configured to perform, in a case that theadmission control result contained in the transfer response received bythe transfer response receiving unit 1008 indicates that the third basestation can not accept all radio bearers of the second base station,admission control for radio bearer unacceptable by the third basestation, so that the radio bearer acceptable by the first bases stationcan be transferred to the first base station 1000.

Also, optionally, the first base station 1000 may further include anotifying unit 1012. The notifying unit 1012 may be configured to notifythe result of the admission control performed by the third base stationand optionally the result of the admission control performed by thefirst base station to the user equipment and/or the second base station.

Further, optionally, the first base station 1000 may further include adata forwarding unit 1014. The data forwarding unit 1014 may beconfigured to perform data forwarding to the third base station in acase that the data of the second base station is forwarded via the firstbase station. Preferably, the data forwarding unit 1014 may perform dataforwarding simultaneously with the second base station after completingthe basic signaling interaction of the transfer procedure, or mayperform the data forwarding only after receiving a message that thesynchronized access between the user equipment and the third basestation succeeds.

Preferably, the first base station 1000 may further include a secondadmission control performing unit 1016. The second admission controlperforming unit 1016 may be configured to perform, in a case that thesynchronized access between the user equipment and the third basestation fails, admission control for the radio bearer that should beaccepted by the third base station originally, so that the radio beareracceptable by the first base station is transferred to the first basestation 1000.

Further, preferably, the first base station 1000 may further include acore network notifying unit 1018. The core network notifying unit 1018may be configured to notify the core network to switch the pathcorresponding to the radio bearer accepted by the first base station tothe first base station in a case that the data of the second basestation comes directly from the core network.

It is to be understood that all of the first admission controlperforming unit 1010, the notifying unit 1012, the data forwarding unit1014, the second admission control performing unit 1016 and the corenetwork notifying unit 1018 are optional, which are shown in broken-lineblocks in FIG. 10, and those skilled in the art may combine one or moreof the above described units as required for example, and any suchcombinations are considered to fall within the scope of the disclosure.

Next, an example of functional configuration of the first base stationserving as the connection maintaining node according to anotherembodiment of the disclosure will be described with reference to FIG.11. FIG. 11 is a block diagram illustrating an example of functionalconfiguration of the first base station serving as the connectionmaintaining node according to another embodiment of the disclosure.Except for providing a receiving unit 1102 instead of the measurementresult receiving unit 1002, the transfer request sending unit 1004, thejudging unit 1006 and the transfer response receiving unit 1008, thefunctional configuration of the first base station 1100 as shown in FIG.11 is the same as that of the first base station 1000 described abovewith reference to FIG. 10, and thus some description will be omitted asappropriate.

The receiving unit 1102 may be configured to receive a notificationregarding the transfer procedure from the second base station or thethird base station serving as the connection transfer target node in acase that the above transfer procedure is triggered by the second basestation serving as the connection transfer source node, and thenotification may include the result of the admission control performedby the third base station.

Further, for the optional first admission control performing unit 1104,the notifying unit 1106, the data forwarding unit 1108, the secondadmission control performing unit 1110 and the core network notifyingunit 1112 as shown in broken-line blocks in FIG. 11, functionalconfigurations thereof are the same as those of corresponding unitsdescribed above with reference to FIG. 10, and no repeated descriptionwill be made herein.

Next, an example of functional configuration of the second base stationserving as the connection transfer source node according to anembodiment of the disclosure will be described with reference to FIG.12. FIG. 12 is a block diagram illustrating an example of functionalconfiguration of the second base station serving as the connectiontransfer source node according to an embodiment of the disclosure.

As shown in FIG. 12, the second base station 1200 according to theembodiment of the disclosure may include a receiving unit 1202. Thereceiving unit 1202 may be configured to receive a notificationregarding the transfer procedure from the first base station or thethird base station serving as the connection transfer target node in acase that the transfer procedure is triggered by the first base stationserving as the connection maintaining node, and the notification mayinclude the result of the admission control performed by the third basestation and optionally the result of the admission control performed bythe first base station.

Optionally, the second base station 1200 may further include a userequipment notifying unit 1204. The user equipment notifying unit 1204may be configured to notify the user equipment of the result of theadmission control performed by the third base station and optionally theresult of the admission control performed by the first base station.

Optionally, the second base station 1200 may further include a dataforwarding unit 1206. The data forwarding unit 1206 may be configured toperform data forwarding operation to the third base station andoptionally the first base station, so as to forward the data of theradio bearers acceptable by the third base station and the first basestation to the third base station and the first base stationrespectively.

Optionally, the second base station 1200 may further include a corenetwork notifying unit 1208. The core network notifying unit 1208 may beconfigured to notify the core network to switch the path correspondingto the radio bearer acceptable by the first base station to the firstbase station in a case that the data of the second base station directlycomes from the core network.

Next, an example of the functional configuration of the second basestation serving as the connection transfer source node according toanother embodiment of the disclosure will be described with reference toFIG. 13. FIG. 13 is a block diagram illustrating an example of thefunctional configuration of the second base station serving as theconnection transfer source node according to another embodiment of thedisclosure. Except for providing a measurement result receiving unit1302, a judging unit 1304, a transfer request sending unit 1306 and atransfer response receiving unit 1308 instead of the receiving unit 1202of the second base station 1200 as shown in FIG. 12, the functionalconfiguration of the second base station 1300 as shown in FIG. 13 is thesame as that of the second base station 1200 as shown in FIG. 12, andthus description thereof will be omitted as appropriate.

The measurement result receiving unit 1302 may be configured to receivea mobility measurement result regarding a serving carrier between theuser equipment and the second base station from the user equipment.

The judging unit 1304 may be configured to judge whether a predeterminedtransfer condition of transferring the services provided to the userequipment by the second base station to the third base station issatisfied according to the mobility measurement result received by themeasurement result receiving unit 1302.

The transfer request sending unit 1306 may be configured to send atransfer request to the third base station serving as the connectiontransfer target node in a case that the judging unit 1304 judges thepredetermined transfer condition is satisfied, so as to trigger the userequipment to release the wireless data connection with the second basestation and establish the wireless data connection with the third basestation, and thus the first base station serving as the connectionmaintaining node and the third base station perform wireless dataconnection with the user equipment over different carriers, so that atleast part of the services originally provided by the second basestation is transferred to the third base station.

The transfer response receiving unit 1308 may be configured to receivefrom the third base station a transfer response which may include theresult of the admission control performed by the third base station.

Further, preferably, the third base station 1300 may further include atransfer confirmation receiving unit 1310. The transfer confirmationreceiving unit 1310 may be configured to receive from the first basestation a transfer confirmation which may include the result of theadmission control performed by the first base station.

Further, for a user equipment notifying unit 1312, a data forwardingunit 1314 and a core network notifying unit 1316 as shown in broken-lineblocks in FIG. 13, functional configurations thereof are the same asthose of the user equipment notifying unit 1204, the data forwardingunit 1206 and the core network notifying unit 1208 described above withreference to FIG. 12, and no repeated description will be made herein.

Further, it is to be noted that similar to the cases as shown in FIGS.10 and 11, the constitute units as shown in broken-line blocks in FIGS.12 and 13 are optional, and those skilled in the art may combine one ormore of these units according to actual requirements, and any suchcombinations are considered to fall within the scope of the disclosure.

Next, an example of functional configuration of the third base stationserving as the connection transfer target node according to anembodiment of the disclosure will be described with reference to FIG.14. FIG. 14 is a block diagram illustrating an example of functionalconfiguration of the third base station serving as the connectiontransfer target node according to an embodiment of the disclosure.

As shown in FIG. 14, the third base station 1400 according to theembodiment of the disclosure may include a transfer request receivingunit 1402, an admission control performing unit 1404 and a transferresponse sending unit 1406.

The transfer request receiving unit 1402 may be configured to receive atransfer request regarding the transfer procedure from the first basestation serving as the connection maintaining node or the second basestation serving as the connection transfer source node which is thetriggering node to make the user equipment release the wireless dataconnection with the second base station, and in a case that thesynchronized access between the user equipment and the third basestation succeeds, the first base station and the third base stationperform wireless data connection with the user equipment over differentcarriers so that at least part of the services originally provided bythe second base station is transferred to the third base station.

The admission control performing unit 1404 may be configured to performthe admission control according to the transfer request received by thetransfer request receiving unit 1402 so as to determine the radio bearerof the second base station acceptable by the third base station.

The transfer response sending unit 1406 may be configured to send atransfer response which may include the result of the admission controlperformed by the third base station to the first base station or thesecond base station which is the triggering node for the transferprocedure.

Optionally, the third base station 1400 may further include a corenetwork notifying unit 1408. The core network notifying unit 1408 may beconfigured to notify the core network to switch the path correspondingto the radio bearer acceptable by the third base station to the thirdbase station in a case that the data of the second base station directlycomes from the core network or the data of the first base station isforwarded via the second base station and the synchronized accessbetween the user equipment and the third base station succeeds.

Further, optionally, the third base station 1400 may further include adata forwarding unit 1410. The data forwarding unit 1410 may beconfigured to perform data forwarding to the first base station in acase that the synchronized access between the user equipment and thethird base station fails, so as to forward the data of the radio beareracceptable by the first base station in the radio bearer originallyaccepted by the third base station to the first base station.

It is to be understood that both of the core network notifying unit 1408and the data forwarding unit 1410 as shown in broken-line blocks in FIG.14 are optional, and those skilled in the art may combine one or more ofthese units according to actual requirements and any such combinationsare considered to fall within the scope of the disclosure.

Next, an example of functional configuration of the user equipmentaccording to an embodiment of the disclosure will be described withreference to FIG. 15. FIG. 15 is a block diagram illustrating an exampleof functional configuration of the user equipment according to anembodiment of the disclosure.

As shown in FIG. 15, the user equipment 1500 according to the embodimentof the disclosure may include a measurement result reporting unit 1502,a first notification receiving unit 1504 and a synchronized accessingunit 1506.

The measurement result reporting unit 1502 may be configured to report amobility measurement result regarding a serving carrier between the userequipment and the second base station serving as the connection transfersource node to the second base station and optionally the first basestation serving as the connection maintaining node, so as to serve asreference for the triggering node to judge whether the predeterminedtransfer condition of transferring the services provided to the userequipment by the second base station to the third base station issatisfied.

The first notification receiving unit 1504 may be configured to receivea notification regarding the transfer procedure from the first basestation or the second base station, and the notification may include theresult of the admission control performed by the third base stationserving as the connection transfer target node and optionally the resultof the admission control performed by the first base station.

The synchronized accessing unit 1506 may be configured to perform thesynchronized access to the third base station according to thenotification received by the first notification receiving unit 1504.

Preferably, the user equipment 1500 may further include a secondnotification receiving unit 1508. The second notification receiving unit1508 may be configured to receive a notification from the first basestation in a case that the synchronized access to the third base stationby the user equipment fails, the notification including informationabout which data of the user equipment may be transmitted over thecarrier of the first base station and which data needs to be released.

Similarly, the second notification receiving unit 1508 as shown inbroken-line block in FIG. 15 is also optional.

It is to be noted that although the examples of the functionalconfigurations of the first base station, the second base station, thethird base station and the user equipment in the wireless communicationsystem according to the embodiments of the disclosure have beendescribed above with reference to FIGS. 10-15, it should be understoodthat this constructs no limitation on the disclosure, and those skilledin the art may combine, sub-combine and alter the above configurationsaccording to the principle of the disclosure.

Next, an example of a procedure of a method used in the wirelesscommunication system according to an embodiment of the disclosure willbe described with reference to FIG. 16. FIG. 16 is a flow chartillustrating an example of a procedure of a method used in the wirelesscommunication system according to an embodiment of the disclosure. Thewireless communication system may include a first base station, a secondbase station, a third base station and user equipment, and the firstbase station and the second base station perform wireless dataconnection with the user equipment over different carriers.

As shown in FIG. 16, the method 1600 according to the embodiment of thedisclosure may include a judging step S1602 and a triggering step S1604.

In the judging step S1602, whether the predetermined transfer conditionof transferring the services provided to the user equipment by thesecond base station to the third base station is satisfied may be judgedby the triggering node. The triggering node may be the first basestation serving as the connection maintaining node or the second basestation serving as the connection transfer source node.

Next, in the triggering step S1604, the transfer procedure may betriggered in a case that it is judged the predetermined transfercondition is satisfied, so as to make the user equipment release thewireless data connection with the second base station and establish thewireless data connection with the third base station, and thus the firstbase station and the third base station perform wireless data connectionwith the user equipment over different carriers. Particularly, at leastpart of the services originally provided by the second base station istransferred to the third base station.

Preferably, the above transfer procedure also causes part of theservices originally provided by the second base station to betransferred to the first base station.

Further, preferably, the triggering node sends a transfer request to thethird base station if it judges the predetermined transfer condition issatisfied according to a received mobility measurement result regardinga serving carrier of the second base station, and the third base stationperforms the first admission control according to the transfer requestand sends a transfer response to the triggering node to notify theresult of the first admission control.

Further, preferably, if the result of the first admission controlindicates that the third base station can not accept all radio bearersbetween the user equipment and the second base station, the first basestation performs the second admission control according to the result ofthe first admission control and notifies the second base station of theresult of the second admission control.

Further, preferably, the first base station or the second base stationsends, after acquiring the final result of the first admission controlor the second admission control, a notification message to the userequipment to notify the user equipment to perform the transfer procedureaccording to the final result and the transfer response of the thirdbase station, the notification message including at least one of thefollowing: for which part of the radio bearer of the user equipment thatthe first base station can perform communication, for which part of theradio bearer of the user equipment that the third base station canperform communication, a dedicated preamble code as required when makingsynchronized access to the third base station, system information of acarrier for communication between the user equipment and the third basestation, and configuration information of a control plane protocol forestablishing communication between the user equipment and the third basestation. Further, the user equipment releases, after receiving thenotification message, the radio bearers unacceptable by the first basestation and the third base station, and releases the wireless dataconnection with the second base station and performs synchronized accessto the third base station at the same time.

It is to be understood that the method used in the wirelesscommunication system according to the embodiment of the disclosurecorresponds to the embodiments of the wireless communication systemdescribed above, and thus parts which are not described in detail hereinmay be referred to the foregoing description at previous correspondingpositions, and no repeated description will be made herein.

Further, the embodiment of the disclosure also provides a storage mediumincluding machine readable program codes which when executed on aninformation processing apparatus, cause the information processingapparatus to perform the method used in the wireless communicationsystem according to the embodiment of the disclosure as described above,the method including the following steps: a judging step of judging, bya triggering node, whether a predetermined transfer condition fortransferring services provided to user equipment by a second basestation to a third base station is satisfied; and a triggering step oftriggering the transfer procedure if it is judged that the predeterminedtransfer condition is satisfied, so that the user equipment releaseswireless data connection with the second base station and establisheswireless data connection with the third base station, and thus a firstbase station and the third base station perform wireless data connectionwith the user equipment over different carriers, wherein at least partof the services originally provided by the second base station istransferred to the third base station. Particularly, the first basestation, the second base station, the third base station and the userequipment are included in a wireless communication system, and the firstbase station and the second base station perform wireless dataconnection with the user equipment over different carriers.

Further, the embodiment of the disclosure also provides a programproduct including machine executable instructions which when executed onan information processing apparatus cause the information processingapparatus to perform the method used in the wireless communicationsystem according to the embodiment of the disclosure as described above,the method including the following steps: a judging step of judging, bya triggering node, whether a predetermined transfer condition fortransferring services provided to user equipment by a second basestation to a third base station is satisfied; and a triggering step oftriggering the transfer procedure if it is judged that the predeterminedtransfer condition is satisfied, so that the user equipment releaseswireless data connection with the second base station and establisheswireless data connection with the third base station, and thus a firstbase station and the third base station perform wireless data connectionwith the user equipment over different carriers, wherein at least partof the services originally provided by the second base station istransferred to the third base station. Particularly, the first basestation, the second base station, the third base station and the userequipment are included in a wireless communication system, and the firstbase station and the second base station perform wireless dataconnection with the user equipment over different carriers.

It should be appreciated that the machine executable instructions in thestorage medium and the program product according to the embodiments ofthe disclosure may also be configured to perform the methodscorresponding to the embodiments of the wireless communication systemdescribed above, and thus parts which are not described in detail hereinmay be referred to description at previous corresponding positions, andno repeated description will be made herein.

Accordingly, a storage medium on which the above program product storingmachine readable instruction codes is carried is also included in thedisclosure of the invention. The storage medium includes but not limitedto a floppy disk, an optical disk, a magneto-optical disk, a storagecard, a memory rod and the like.

Furthermore, it shall be noted that the foregoing series of processesand apparatuses can also be embodied in software and/or firmware. In thecase of being embodied in software and/or firmware, a programconstituting the software is installed from a storage medium or anetwork to a computer with a dedicated hardware structure, e.g., ageneral purpose personal computer 1700 illustrated in FIG. 17, which canperform various functions when various programs are installed thereon.

In FIG. 17, a Central Processing Unit (CPU) 1701 performs variousprocesses according to a program stored in a Read Only Memory (ROM) 1702or loaded from a storage portion 1708 into a Random Access Memory (RAM)1703 in which data required when the CPU 1701 performs the variousprocesses is also stored as needed.

The CPU 1701, the ROM 1702 and the RAM 1703 are connected to each othervia a bus 1704 to which an input/output interface 1705 is alsoconnected.

The following components are connected to the input/output interface1705: an input portion 1706 including a keyboard, a mouse, etc.; anoutput portion 1707 including a display, e.g., a Cathode Ray Tube (CRT),a Liquid Crystal Display (LCD), etc., a speaker, etc.; a storage portion1708 including a hard disk, etc.; and a communication portion 1709including a network interface card, e.g., an LAN card, a modem, etc. Thecommunication portion 1709 performs a communication process over anetwork, e.g., the Internet.

A driver 1710 is also connected to the input/output interface 1705 asneeded. A removable medium 1711, e.g., a magnetic disk, an optical disk,an magneto optical disk, a semiconductor memory, etc., can be installedon the driver 1710 as needed so that a computer program fetchedtherefrom can be installed into the storage portion 1808 as needed.

In the case that the foregoing series of processes are performed insoftware, a program constituting the software is installed from anetwork, e.g., the Internet, etc., or a storage medium, e.g., theremovable medium 1711, etc.

Those skilled in the art shall appreciate that such a storage mediumwill not be limited to the removable medium 1711 illustrated in FIG. 17in which the program is stored and which is distributed separately fromthe device to provide a user with the program. Examples of the removablemedium 1711 include a magnetic disk (including a Floppy Disk (aregistered trademark)), an optical disk (including Compact Disk-ReadOnly memory (CD-ROM) and a Digital Versatile Disk (DVD)), a magnetooptical disk (including a Mini Disk (MD) (a registered trademark)) and asemiconductor memory. Alternatively the storage medium can be the ROM1702, a hard disk included in the storage portion 1708, etc., in whichthe program is stored and which is distributed together with theapparatus including the same to the user.

It shall further be noted that the steps of the foregoing series ofprocesses may naturally but not necessarily be performed in thesequential order as described chronically. Some of the steps may beperformed concurrently or separately from each other.

Although the disclosure and the advantages thereof have been describedin details, it shall be appreciated that various modifications,substitutions and variations can be made without departing from thespirit and scope of the disclosure as defined by the appended claims.Furthermore, the terms “include”, “comprise” or any variants thereof inthe embodiments of the disclosure are intended to encompass nonexclusiveinclusion so that a process, method, article or apparatus including aseries of elements includes both those elements and other elements whichare not listed explicitly or an element(s) inherent to the process,method, article or apparatus. Without much more limitation, an elementbeing defined by a sentence “include/comprise a(n) . . . ” will notexclude presence of an additional identical element(s) in the process,method, article or apparatus including the element.

The invention claimed is:
 1. An electronic device for an anchor node ina communication system comprising the anchor node, a source node, atarget node and a user equipment, the electronic device comprisingcircuitry, configured to initiate a change procedure by requesting thetarget node to admit radio bearers of the user equipment in case that apredetermined condition of changing the source node which serves theuser equipment together with the anchor node over different carriers tothe target node is satisfied; acquire an acknowledgment from the targetnode which includes a result of radio bearers admission; and indicateconfiguration information of the target node towards the user equipmentfor releasing the source node and accessing to the target node, whereinthe anchor node is kept in connection with the user equipment to jointlyserve the user equipment with the source node or the target node,wherein the circuitry is further configured to forward data of the userequipment to the target node.
 2. The device according to claim 1,wherein the circuitry is further configured to indicate the source nodeof information in the result of radio bearers admission for dataforwarding to the target node.
 3. The device according to claim 1,wherein the circuitry is further configured to acquire data of the userequipment forwarded from the source node.
 4. The device according toclaim 1, wherein the configuration information of the target nodecomprising at least one of the following: which part of radio bearers ofthe user equipment that the anchor node admits, which part of the radiobearer of the user equipment that the target node admits, a dedicatedpreamble code as required for accessing to the target node, systeminformation relating to the target node, and configuration informationof a control plane protocol for establishing communication between theuser equipment and the target node.
 5. The device according to claim 1,wherein the anchor node corresponds to a base station.
 6. An electronicdevice for a target node in a communication system comprising an anchornode, a source node, the target node and a user equipment, theelectronic device comprising circuitry, configured to acquire a requestfrom the anchor node which initiates a change procedure by requestingthe target node to admit radio bearers of the user equipment in casethat a predetermined condition of changing the source node which servesthe user equipment together with the anchor node over different carriersto the target node is satisfied; make an acknowledgment to the anchornode which includes a result of radio bearers admission; and receiveaccess request from the user equipment based on configurationinformation of the target node to establish synchronization between theuser equipment and the target node, wherein the anchor node is kept inconnection with the user equipment to jointly serve the user equipmentwith the source node or the target node, wherein the circuitry isfurther configured to acquire data of the user equipment forwarded fromthe anchor node.
 7. The device according to claim 6, wherein theconfiguration information of the target node comprising at least one ofthe following: which part of radio bearers of the user equipment thatthe anchor node admits, which part of the radio bearer of the userequipment that the target node admits, a dedicated preamble code asrequired for accessing to the target node, system information relatingto the target node, and configuration information of a control planeprotocol for establishing communication between the user equipment andthe target node.
 8. The device according to claim 6, wherein the targetnode corresponds to a small base station.
 9. An electronic device for asource node in a communication system comprising an anchor node, thesource node, a target node and a user equipment, the electronic devicecomprising circuitry, configured to release a connection between theuser equipment and the source node which serves the user equipmenttogether with the anchor node over different carriers in response to achange procedure initiated by the anchor node by requesting the targetnode to admit radio bearers of the user equipment in case that apredetermined condition of changing the source node to the target nodeis satisfied; acquire an indication from the anchor node includinginformation in a result of radio bearers admission of the target node;and forward data to at least one of the anchor node and the target nodebased on the indication, wherein the anchor node is kept in connectionwith the user equipment to jointly serve the user equipment with thesource node or the target node.
 10. An electronic device for a userequipment in a communication system comprising an anchor node, a sourcenode, a target node and the user equipment, the electronic devicecomprising circuitry, configured to acquire configuration information ofthe target node from the anchor node in response to a change procedurewhich is initiated by the anchor node by requesting the target node toadmit radio bearers of the user equipment in case that a predeterminedcondition of changing the source node which serves the user equipmenttogether with the anchor node over different carriers to the target nodeis satisfied; release the source node and access to the target nodebased on the configuration information; and receive data which isforwarded by the source node to at least one of the anchor node and thetarget node based on a result of radio bearers admission of the targetnode; wherein the anchor node is kept in connection with the userequipment to jointly serve the user equipment with the source node orthe target node.
 11. The device according to claim 10, wherein theconfiguration information of the target node comprising at least one ofthe following: which part of radio bearers of the user equipment thatthe anchor node admits, which part of the radio bearer of the userequipment that the target node admits, a dedicated preamble code asrequired for accessing to the target node, system information relatingto the target node, and configuration information of a control planeprotocol for establishing communication between the user equipment andthe target node.
 12. A communication method for an anchor node in acommunication system comprising the anchor node, a source node, a targetnode and a user equipment, the method comprising initiating, usingcircuitry, a change procedure by requesting the target node to admitradio bearers of the user equipment in case that a predeterminedcondition of changing the source node which serves the user equipmenttogether with the anchor node over different carriers to the target nodeis satisfied; acquiring an acknowledgment from the target node whichincludes a result of radio bearers admission; and indicatingconfiguration information of the target node towards the user equipmentfor releasing the source node and accessing to the target node, whereinthe anchor node is kept in connection with the user equipment to jointlyserve the user equipment with the source node or the target node,wherein the method further comprises forwarding data of the userequipment to the target node.
 13. The method according to claim 12,wherein the method further comprises indicating the source node ofinformation in the result of radio bearers admission for data forwardingto the target node.
 14. The method according to claim 12, wherein themethod further comprises acquiring data of the user equipment forwardedfrom the source node.
 15. The method according to claim 12, wherein theconfiguration information of the target node comprising at least one ofthe following: which part of radio bearers of the user equipment thatthe anchor node admits, which part of the radio bearer of the userequipment that the target node admits, a dedicated preamble code asrequired for accessing to the target node, system information relatingto the target node, and configuration information of a control planeprotocol for establishing communication between the user equipment andthe target node.
 16. A communication method for a target node in acommunication system comprising an anchor node, a source node, thetarget node and a user equipment, the method comprising acquiring, usingcircuitry, a request from the anchor node which initiates a changeprocedure by requesting the target node to admit radio bearers of theuser equipment in case that a predetermined condition of changing thesource node which serves the user equipment together with the anchornode over different carriers to the target node is satisfied; making anacknowledgment to the anchor node which includes a result of radiobearers admission; and receiving access request from the user equipmentbased on configuration information of the target node to establishsynchronization between the user equipment and the target node, whereinthe anchor node is kept in connection with the user equipment to jointlyserve the user equipment with the source node or the target node,wherein the method further comprises acquiring data of the userequipment forwarded from the anchor node.
 17. The method according toclaim 16, wherein the configuration information of the target nodecomprising at least one of the following: which part of radio bearers ofthe user equipment that the anchor node admits, which part of the radiobearer of the user equipment that the target node admits, a dedicatedpreamble code as required for accessing to the target node, systeminformation relating to the target node, and configuration informationof a control plane protocol for establishing communication between theuser equipment and the target node.
 18. A communication method for asource node in a communication system comprising an anchor node, thesource node, a target node and a user equipment, the method comprisingreleasing, using circuitry, a connection between the user equipment andthe source node which serves the user equipment together with the anchornode over different carriers in response to a change procedure initiatedby the anchor node by requesting the target node to admit radio bearersof the user equipment in case that a predetermined condition of changingthe source node to the target node is satisfied; acquiring an indicationfrom the anchor node including information in a result of radio bearersadmission of the target node; and forwarding data to at least one of theanchor node and the target node based on the indication, wherein theanchor node is kept in connection with the user equipment to jointlyserve the user equipment with the source node or the target node.
 19. Acommunication method for a user equipment in a communication systemcomprising an anchor node, a source node, a target node and the userequipment, the method comprising acquiring, using circuitry,configuration information of the target node from the anchor node inresponse to a change procedure which is initiated by the anchor node byrequesting the target node to admit radio bearers of the user equipmentin case that a predetermined condition of changing the source node whichserves the user equipment together with the anchor node over differentcarriers to the target node is satisfied; releasing the source node andaccessing to the target node based on the configuration information; andreceiving data which is forwarded by the source node to at least one ofthe anchor node and the target node based on a result of radio bearersadmission of the target node; wherein the anchor node is kept inconnection with the user equipment to jointly serve the user equipmentwith the source node or the target node.
 20. The method according toclaim 19, wherein the configuration information of the target nodecomprising at least one of the following: which part of radio bearers ofthe user equipment that the anchor node admits, which part of the radiobearer of the user equipment that the target node admits, a dedicatedpreamble code as required for accessing to the target node, systeminformation relating to the target node, and configuration informationof a control plane protocol for establishing communication between theuser equipment and the target node.
 21. A non-transitory computerreadable storage medium encoded with computer-readable instructionsthereon, the computer-readable instructions, when executed by acomputer, cause the computer to perform a communication method for auser equipment in a communication system comprising an anchor node, asource node, a target node and the user equipment, the communicationmethod comprising acquiring configuration information of the target nodefrom the anchor node in response to a change procedure which isinitiated by the anchor node by requesting the target node to admitradio bearers of the user equipment in case that a predeterminedcondition of changing the source node which serves the user equipmenttogether with the anchor node over different carriers to the target nodeis satisfied; releasing the source node and accessing to the target nodebased on the configuration information; and receiving data which isforwarded by the source node to at least one of the anchor node and thetarget node based on a result of radio bearers admission of the targetnode; wherein the anchor node is kept in connection with the userequipment to jointly serve the user equipment with the source node orthe target node.